Although it isn't that bad here, ozone levels have risen with the temperatures, and state and local agencies are urging people, particularly the young and the old, to take precautions.

People with respiratory diseases and young children should cut back on outdoor activities, the Allentown Bureau of Health warned Thursday. Finding cool places and consuming lots of nonalcoholic, decaffeinated drinks also are recommended.

While most area hospitals reported no heat-related problems Thursday, St. Luke's in Fountain Hill reported that two elderly people were brought in with dehydration.

Thursday's high temperature was 91 degrees, according to the National Weather Service, which expects this weekend to be the hottest yet this year, with temperatures predicted above 90 today and Saturday and in the mid- to upper 80s Sunday.

High temperatures often mean higher levels of ground-level ozone, or smog. Ozone is produced when nitrogen oxides, principally from motor vehicles, mix in sunlight with volatile organic compounds, which come from motor vehicles, refineries and other smokestack industries. The pollutant causes breathing and other health problems, with senior citizens, children and asthmatics especially susceptible.

To reduce ozone, the Department of Environmental Protection recommends cutting back on the use of automobiles and lawnmowers, two major sources of ozone-causing pollutants, said Jerry Zvirblis, operations chief in the DEP's air quality section in Wilkes-Barre.

Zvirblis also suggested avoiding topping off your car's gas tank, especially during daylight hours when evaporation from the gas pump nozzle and tank is more rapid.

"All that adds to the problem," he said.

Environmental groups seized this week on the onset of summer and rising temperatures to criticize attempts to roll back stricter air-quality standards adopted last June. And one health organization called for even tougher ozone standards.

The American Lung Association said this week that stricter standards imposed by President Clinton last summer to clean smog and soot from the air above U.S. cities and rural areas over the next 15 years don't go far enough.

The standards were intended to reduce the number of deaths, illness and lost work days linked to air pollution.

The association said the new limits have already been exceeded in at least 30 states. It wants the U.S. Environmental Protection Agency to require smog-fighting, low-sulphur gasoline nationwide and to adopt stricter tailpipe standards for future automobiles.

Environmentalists warned this week that power industry lobbyists are trying to block ozone reduction efforts.

The industry is working to convince the governors of nine states, including Gov. Tom Ridge of Pennsylvania, to back away from a plan to control pollution that drifts from one state to another.

Zvirblis said some areas of Pennsylvania already are in violation of the new smog standards because of pollution drifting in from neighboring states.

"The governor is aware of it," he said. "The state has problems accepting the new standard unless the federal government does something to make the other states reduce their ozone."